Chronometer的使用

Chronometer控件布局文件如下

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/widget139"
    >
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/btn1"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true"
        android:text="倒计时"
        android:onClick="countDown"
        />
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/btn2"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true"
        android:layout_below="@+id/btn1"
        android:text="顺计时"
        android:onClick="countUp"
        />
    <Chronometer
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@id/btn1"
        android:layout_centerHorizontal="true"
        android:id="@+id/chronometer"
        android:visibility="visible"
        />

</RelativeLayout>

处理代码如下

package com.idt.os.mychronoscopeapp;

import android.graphics.Color;
import android.os.Bundle;
import android.os.SystemClock;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Chronometer;

public class MainActivity extends AppCompatActivity {
    private Chronometer chronometer;
    private final int DOWN_COUNTER_TIMER = 10000;   //10秒
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        chronometer = (Chronometer) findViewById(R.id.chronometer);
        chronometer.setTextSize(100);        //字体大小
        chronometer.setTextColor(Color.RED);    //字体颜色
        chronometer.setFormat("%s");    //设置计时器显示格式
    }

    public void countDown(View view) {
        chronometer.setBase(SystemClock.elapsedRealtime()+DOWN_COUNTER_TIMER); //设置计时时基   
        chronometer.setCountDown(true);     //倒计时

        final long base = chronometer.getBase();
            chronometer.start();    //启动计时
        chronometer.setOnChronometerTickListener(new Chronometer.OnChronometerTickListener() {
            @Override
            public void onChronometerTick(Chronometer chronometer) {
                long time = SystemClock.elapsedRealtime();    /获取系统时间

                if(time >= base) {
                    if(chronometer.isCountDown())    //是否是倒计时
                       chronometer.stop();     //停止计时
                }

            }
        });


    }

    public void countUp(View view) {

        chronometer.setBase(SystemClock.elapsedRealtime());    //设置计时时基
        chronometer.setCountDown(false);    //顺计时

        chronometer.start();    //启动计时
    }
}